<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    #grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      grid-template-rows: repeat(3, 1fr);
      grid-auto-flow: row dense;
    }

    li {
      grid-row: auto;
      grid-column: 1 / span 2;
    }

    li:nth-child(3),
    li:nth-child(5) {
      grid-column: auto;
    }
  </style>
</head>
<body>
  <ol id="grid">
    <li>1</li>
    <li>2</li>
    <li>3</li>
    <li>4</li>
    <li>5</li>
  </ol>
</body>
</html>